body{
  margin: 0;
}
#wrapper{
  height: 800px;
  width: 500px;
  margin: 0 auto;
  border: 1px solid #000;
  box-sizing: border-box;
  overflow: auto;
}

.item{
  height: 50px;
  line-height: 50px;
  text-align: center;
  border-bottom: 1px solid #ccc;
  background-color: antiquewhite;
  box-sizing: border-box;
}